The purpose of this trial is to assess the short term safety and preliminary efficacy of intravenous HPMPC (Cidofovir) for treatment of small peripheral CMV retinitis lesions in patients with AIDS via a comparative randomized trial of HPMPC vs. observation (no treatment) in an initial study population of up to 30 patients across 13 clinical centers. The purpose is also to evaluate the longer term safety, tolerance and efficacy of two regimens of intravenous HPMPC for treatment of CMV retinitis in patients with AIDS.